Rotary gravel screen or grader.



1-. .P. LOCKWOOD.

ROTARY GRAVEL SCREEN 0R GRADER APPLICATION FILED OCT. 5. ms

Patented 0ct.1(),1916.

JOHN P. LOCKWOOD,- OF HOWELL, MICHIGAN.

ROTARY GRAVEL SCREEN OR GRADER.

Specification of Letters Patent.

Patented. (let. it 19143..

7 Application filed October 5, 1915. Serial No. 54,263.

T o (ZN/107L077? it may concern Be it known that 1, JOHN P. Locnwoon, a citizen of the United States, residing at Howell, county of Livingston, State of Michigan, have invented a certain new and useful Improvement 'in Rotary Gravel Screens or Graders, and declare the follow-..

ing to be a full, clear, and exact descrip tion of the same, such as will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

This invention relates to rotary screens for gravel and sand, and has for its object an improved construction adapted to-rapidly and efficiently separate the sand and the various grades or sizes of gravel from one another, as contrasted with the mingled conditions in which the material comes from the gravel pit, and itis of assistance, not only in dealing with the wet and caked condition of the sand which is often encountered, but as well with the disposition of occasional large stones, whose diameter is such as to make them unfit for classification as any kind of gravel.

In the drawings: Figure 1 is a perspective of the device. Fig. 2 is a lengthwise elevation of the device, partly in section.

Fig. 3 isan end sectional elevation along the line of Fig. 2.

A represents a perforated cylinder or shell, various zones or annular sections of which are perforated with progressively sized holes, B, C and D, the holes of the smaller size B being located at the receiving end of the cylinder, which is raised slightly above the lower or delivery end where the largest holes I) are located.

, The device, as a Whole, is .rotatably sus-v pended upon a shaft E, which may, or maynot, extend throughout the length of the cylinder, and which, in either case, is held in concentric position with respect to the shell A by means of the spiders F located at each. end, perferablyslightly inside the extreme end. The shaft is adapted to be rotated by any desired means, either manually or by an engine.

concentrically arranged about the upper end of the cylinder A, where the small holes 13 are-located, s a Wire screen, orsieve G, "which is held properly spaced from the cylind'r A by struts or braces H at desired intervals at the periphery of the cylinder.

The various constituent wires or strips J are held suitably spaced. from one another by serrated or notched strips K, to which the wires maybe secured as firmly as may be desired by notching of the strip K, sol

dering, wiring, or any other desired means.

A skirting or guard band M may, if desired, be employed to close the upper edge or end of the space between the cylinder A and the wire sieve G against the escape of sand and fine gravel which has fallen, or been thrown by centrifugal force, through the small holes 33.

T he sandy gravel, as it comes from the pit,

is fed into the raised inlet end of the rotating cylinder by means of the feed spout L,

and first encounters that portion of the shell in. which the small perforations B are located. Due to the rotation of the shell, together with the line character of the sand, considerable centrifugal force is exerted thereon, so that if that portion of the shell had no additional piece as the wire sieve (1?, not a few pebbles would be projected therethrough and into the sand bin N. With this protection, however, these undesired pieces are held and gradually tumbled. due to the slanting of the cylinder as a whole, toward the wall which divides the sand bin N from the fine gravel bin G, into which they then fall, together with the gravel that is released through the holes C, of medium size. Somewhat larger stones, which cannot escape through the holes C, continue on their course to that part of the cylinder in which the holes D are located, falling thence into the coarse gravel bin P Any larger pebbles or cobblestones which cannot thus escape 1nto another bin. for such d1sposit1on as may be des1red.- Of

course, in some cases. two diii'erent sizes of holes in the shell will be found to. be enough, while in other cases, more than three different sizes may be desired.

The angle at which the shell or cylinder A is tilted for rotation, as well as its speed of rotation, largely determines the speed with which the unsorted sand and gravel passes lengthwise of the cylinder. Ordina rily a twenty-five degree angle from the horizontal is sufiicient, but if finer screening and a longer period of tumbling-of the material is desired, this angle may be diminished somewhat with good results; similarly, if not such fine grading of theunsorted material is desired, the-shell A may be tilted in clampedposition aboutthe cylinder A.

I shell,

What I claim is: v

1. In an apparatus of the class described, I the combination with a rotatable perforated shell, of a screen member spaced from and concentrically disposed around said said screen member comprising a series of wire elements disposed perpendicularly to the axis of said shell, said Wire elements being spaced apart by a plurality of brace bars, the ends ofeach wire element being clamped together by two adjacent brace bars.

perforated cylinder, of a screen member concentrically surrounding one end thereof and spaced therefrom, said 2. In a device-of the class described, the combination with a screen member comprising a plurality of substantially parallel wires, bars for holding said wires in parallel relation, and an adjustable member surrounding said bars and securing all of the parts'in operative position.

3. In a device of the class described, the

combination with a perforated cylinder, of a screen member concentrlcall surrounding one end thereof and spaced therefrom, said,

screen member comprising a plurality of substantially parallel wires, bars A for holding said wires in supporting said screen, and an adjustable member surrounding said bars and attached to said struts for securing allof the parts in operative relation;

In testimonywhereof, I sign this specification in the presence of two Witnesses.

JOHN P LOCKWOOD.

Witnesses:

' WILLIAM M. SWAN,

-JEFFERSON G. THURBER.

Copies of this patent may be obtained to! five cents'each, by addressing the commissioner of rat'ents; Washington, D. O. Y a

parallel relation, struts 

